Polymer latex

Abstract

The present invention relates to a polymer latex comprising: (A) particles of a latex polymer (A) obtainable by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers the latex polymer comprising a plurality of functional groups (x); and (B) a compound bearing a beta-hydroxy ester linkage and at least one additional functional group (y) reactive with the functional groups (x) on latex polymer (A), to a method for preparation of said polymer latex, to its use, to a method for dip-molding and to articles obtained from the latex.

1 . A polymer latex for the preparation of elastomeric films comprising:
 (A) particles of a latex polymer (A) obtainable by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers the latex polymer comprising a plurality of functional groups (x); and   (B) a compound bearing a beta-hydroxy ester linkage and at least one additional functional group (y) reactive with the functional groups (x) on latex polymer (A).   
     
     
         2 . The latex polymer of  claim 1 , wherein the functional groups (x) on the latex polymer (A) are selected from groups having a carbon-carbon double bond, carboxylic acid functional groups, hydroxyl, epoxy, acetoacetyl, primary or secondary amino, acetoxy, isocyanato, alkoxysilyl, alkoxy, dioxolanone functional groups and combinations thereof. 
     
     
         3 . The latex polymer of  claim 1  wherein the monomer composition for the latex polymer (A) comprises
 (a) 15 to 99 wt.-% of conjugated dienes; 
 (b) 1 to 80 wt.-% of monomers selected from ethylenically unsaturated nitrile compounds; 
 (c) 0 to 10 wt.-% of an ethylenically unsaturated compound different from conjugated dienes bearing a functional group (x); 
 (d) 0 to 80 wt.-% of vinyl aromatic monomers; and 
 (e) 0 to 65 wt.-% of alkyl esters of ethylenically unsaturated acids, 
 the weight percentages being based on the total weight of monomers in the monomer mixture. 
     
     
         4 . The polymer latex of  claim 3  wherein
 (a) the conjugated dienes are selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and combinations thereof; 
 (b) the ethylenically unsaturated nitrile compounds are selected from (meth)acrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alpha-chloronitrile and combinations thereof; 
 (c) the ethylenically unsaturated compounds different from conjugated dienes bearing a functional group (x) are selected from
 (c1) ethylenically unsaturated compounds having at least two different ethylenically unsaturated groups; 
 (c2) ethylenically unsaturated acids and salts thereof; 
 (c3) hydroxy functional ethylenically unsaturated compounds; 
 (c4) oxirane functional ethylenically unsaturated compounds; 
 (c5) acetoacetyl functional ethylenically unsaturated compounds; 
 (c6) ethylenically unsaturated compounds bearing a primary or secondary amino group; 
 (c7) acetoxy functional ethylenically unsaturated compounds; 
 (c8) isocyanato functional ethylenically unsaturated compounds; 
 (c9) alkoxysilyl functional ethylenically unsaturated compounds; 
 (c10) alkoxy functional ethylenically unsaturated compounds; 
 (c11) dioxolanone functional ethylenically unsaturated compounds; 
 and combinations thereof; 
 
 (d) the vinyl aromatic monomers are selected from styrene, alpha-methyl styrene and combinations thereof; 
 (e) alkyl esters of ethylenically unsaturated acids are selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate; 
 and combinations thereof; 
 the mixture of ethylenically unsaturated monomers for latex polymer (A) optionally comprises ethylenically unsaturated monomers selected from 
 (f) vinyl carboxylates; 
 (g) monomers having at least two identical ethylenically unsaturated groups; and 
 combinations thereof. 
 
     
     
         5 . The polymer latex of  claim 1 , wherein the mixture of ethylenically unsaturated monomers for latex polymer (a) comprises:
 20 to 99 wt.-% of conjugated dienes;   1 to 60 wt.-% of monomers selected from ethylenically unsaturated nitrile compounds;   0 to 70 wt.-% of vinyl aromatic monomers;   0 to 25 wt.-% of C 1  to C 8  alkyl (meth)acrylates;   0.05 to 7 wt.-% of ethylenically unsaturated acids; and   0 to 10 wt.-% of vinyl esters:   the weight percentages being based on the total weight of monomers in the monomer mixture.   
     
     
         6 . The polymer latex of  claim 1 , wherein the functional groups (y) in compound (B) reactive with the functional groups (x) on latex polymer (A) are selected from carbon-carbon double bonds, epoxy, thiol, hydroxy, primary or secondary amino, isocyanato, oxazolino, aziridino, imino, carbodiimido, glycol groups, ester groups, acetoxy, carboxylic acid groups, alkoxy silyl groups, dioxolanone groups, hydrazido, and combinations thereof. 
     
     
         7 . The polymer latex of  claim 1 , wherein the functional groups (y) in compound (B) are in a terminal position. 
     
     
         8 . The polymer latex of  claim 1 , wherein
 the functional groups (x) are selected from groups having a carbon-carbon double bond and the functional groups (y) are selected from groups having carbon-carbon double bonds and thiol; or   the functional groups (x) are selected from carboxylic acid functional groups and the functional groups (y) are selected from epoxy, thiol, hydroxy, primary or secondary amino, isocyanato, oxazolino, aziridino, imino, carbodiimido, glycol groups, ester groups, and acetoxy; or   the functional groups (x) are selected from hydroxyl and the functional groups (y) are selected from alkoxysilyl, carboxylic acid functional groups; isocyanato, primary or secondary amino, and ester groups; or   the functional groups (x) are selected from epoxy and the functional groups (y) are selected from carboxylic acid functional groups, hydroxyl and ester groups; or   the functional groups (x) are selected from acetoacetyl and the functional groups (y) are selected from groups having carbon-carbon double bonds, isocyanato and primary or secondary amino; or   the functional groups (x) are selected from primary or secondary amino and the functional groups (y) are selected from carboxylic acid functional groups, epoxy, ester groups and dioxolanone groups; or   the functional groups (x) are selected from acetoxy and the functional groups (y) are selected from hydrazido and primary or secondary amino; or   the functional groups (x) are selected from isocyanato and the functional groups (y) are selected from carboxylic acid functional groups. hydroxyl, primary or secondary amino and thiol; or   the functional groups (x) are selected from alkoxysilyl and the functional groups (y) are selected hydroxyl and alkoxysilyl; or   the functional groups (x) are selected from alkoxy and the functional groups (y) are selected from ester groups; or   the functional groups (x) are selected from ester groups and the functional groups (y) are selected from hydroxyl, carboxylic acid groups and ester groups; or   the functional groups (x) are selected from dioxolanone groups and the functional groups (y) are selected from primary or secondary amino.   
     
     
         9 . The polymer latex of  claim 1 , wherein compound (B) is selected from glycerol dimethacrylate (GDMA), glycerol 1,3-diglycerolate diacrylate (GDGDA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, bisphenol A glycerolate diacrylate, levulinic acid methacrylate (KEMA), glyceryl monomethacrylate, fatty acid modified glycidyl methacrylate Bisphenol A glycerolate diacrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, eugenyl-2-hydroxypropyl methacrylate and combinations thereof. 
     
     
         10 . The polymer latex of  claim 1 , wherein the particles of latex polymer (A) are present in amounts of 80 to 99.9 wt.-% and compound (B) is present in amounts of 0.1 to 20 wt. based on the total weight of latex polymer (A) and compound (B). 
     
     
         11 . A method for preparation of a polymer latex comprising
 (i) polymerizing in an emulsion polymerization process a mixture of ethylenically unsaturated monomers for latex polymer (A) comprising at least one monomer resulting after polymerization in a functional group (x) to obtain a latex comprising particles of latex polymer (A) bearing a plurality of functional groups (x); and   (ii) adding a compound (B) bearing a beta-hydroxy ester linkage and at least one additional functional group (y) reactive with the functional groups (x) on latex polymer (A).   
     
     
         12 . The method of  claim 11 , wherein the functional groups (x) on the latex polymer (A) are selected from groups having a carbon-carbon double bond, carboxylic acid functional groups, hydroxyl, epoxy, acetoacetyl, primary or secondary amino, acetoxy, isocyanato, alkoxvsilvl, alkoxy, dioxolanone functional groups and combinations thereof, and wherein the at least one additional functional group (y) is selected from carbon-carbon double bonds, epoxy, thiol, hydroxy, primary or secondary amino, isocyanato, oxazolino, aziridino, imino, carbodiimido, glycol groups, ester groups, acetoxy, carboxylic acid groups, alkoxy silyl groups, dioxolanone groups, hydrazido, and combinations thereof. 
     
     
         13 . Use of the polymer latex according to  claim 1  for the production of elastomeric articles or for coating or impregnating a substrate. 
     
     
         14 . A compounded latex composition suitable for the production of dip-molded articles comprising the polymer latex according to  claim 1  and optionally adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, polyvalent cations, free-radical initiators and combinations thereof. 
     
     
         15 . The compounded latex composition of  claim 14 , being free of sulfur vulcanization agents and accelerators for sulfur vulcanization and optionally comprising polyvalent cations. 
     
     
         16 . A method for making dip-molded articles by
 a) providing a compounded latex composition of  claim 14 ;   b) immersing a mold having the desired shape of the final article in a coagulant bath comprising a solution of a metal salt;   c) removing the mold from the coagulant bath and optionally drying the mold;   d) immersing the mold as treated in step b) and c) in the compounded latex composition of step a);   e) coagulating a latex film on the surface of the mold;   f) removing the latex-coated mold from the compounded latex composition and optionally immersing the latex-coated mold in a water bath;   g) optionally drying the latex-coated mold;   h) heat treating the latex-coated mold obtained from step e) or f) at a temperature of 40° C. to 180° C.; and/or exposing the latex-coated mold obtained from step e) or f) to UV radiation;   i) removing the latex article from the mold.   
     
     
         17 . A method for making elastomeric articles comprising:
 obtaining a continuous elastomeric film from the polymer latex according to  claim 1 ;   optionally heat treating the continuous elastomeric film and/or exposing the continuous elastomeric film to UV radiation;   aligning two separate continuous elastomeric films;   cutting or stamping the aligned continuous elastomeric films into a preselected shape to obtain two superposed layers of the elastomeric films in the preselected shape;   joining together the superposed layers at at least a preselected part of the periphery to form an elastomeric article.   
     
     
         18 . The method of  claim 17 , wherein the joining together is performed by using thermal means. 
     
     
         19 . An article made by using the polymer latex according to  claim 1 . 
     
     
         20 . The article of  claim 19 , being selected from surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves, household gloves balloons and tubing.